Silencer for internal-combustion engines



Jan. 8, 1946. D. c. VAR'MA 2,392,559

SILENCER FOR INTERNAL-COMBUSTION ENG INES Filed March 15 1944 Inventor A ttorneys- Patented Jan. 8, 1946 SILENCER FOR INTERNAL-COMBUSTION ENGINES Dewan Chand Vanna, London, England Application March 15, 1944, Serial No. 526,561 r In Great Britain February 5, 1943 9 Claims.

This invention relates to silencers for internal combustion engines of the kind comprising expansion chambers and bafiles whereby energy is absorbed from the exhaust gases before they are discharged to the atmosphere.

An exhaust silencer according to this invention comprises at least one primary expansion chamber packed with separate metallic balls, and at least one secondary expansion chamber packed with interstitial refractory material, the exhaust gases expanding into the interstices in the two packings on their way to the outlet end of the silencer.

Preferably the gases enter and leave each expansion chamber through baffie tubes or passages which cause the gases to enter and leave each chamber transversely to the longitudinal axes of the baille tubes. The inlet end of the silencer may be furnished with a conical plug or tube fiaring towards the adjacent expansion chamber and having its conical wall perforated so that the gases enter in directions transverse to the longitudinal axis of the cone. Similarly, the outlet end of the silencer may be provided with a conical plug or tube flaring towards the adjacent expansion chamber and having its conical wall perforated so that the gases escape to the atmosphere in directions transverse to the longitudinal axis of the cone.

The invention may be carried into practice in various ways, but one arrangement according to the invention, together with a modification thereof, is shown by way of example in the accompanying drawing, in which t Figure 1 shows one arrangement in side elevaion, Figure 2 is a longitudinal section, and

Figure 3 is a view similar to that of Figure 2 but of a modified arrangement.

In the construction shown in Figures 1 and 2 the silencer comprises an outer cylindrical metal casing A in opposite ends of which respectively are secured two spherical chambers B and C also of metal and packed with metal balls B C such for example as of the type normally employed in ball bearings. The annular chamber A formed within the outer cylindrical casing A between the two spherical chambers B and C has a filling of interstitial refractory material, such for example as asbestos fibre.

Extending a short distance into the spherical chamber C at one end of the silencer is an inlet tube D which, when the silencer is in use, is coupled to the exhaust manifold of the engine, and disposed within this tube D adjacent to the spherical chamber C (hereinafter referred to as the primary expansion chamber) is a conical tubular insert D which flares towards the adjacent primary expansion chamber C and has its conical surface, which is presented to the exhaust gases, perforated so that the gases are caused to flow inwards in directions transverse to the longitudinal axis of the cone D, that is to ay the longitudinal axis of the inlet tube D. The inner end of the inlet tube D lying within the primary expansion chamber C is closed by a transverse baflle wall D but the cylindrical wall D of the inlet tube lying within this chamber C is perforated so that the incoming gases will enter the primary expansion chamber C in directions transverse to the longitudinal axis of the inlet tube D, these gases then expanding into the interstices formed between the metal balls C Extending through the inner wall of the primary expansion chamber C and into the annular chamber A between the two spherical chambers B and C is a short length of tube E closed at both ends by transverse bafile walls E perforations being however formed in the cylindrical end portion of the tube E, lying in the two adjacent expansion chambers C, A respectively. The exhaust gases thus leave the primary expansion chamber C and enter the chamber A filled with refractory material (hereinafter referred to as the secondary expansion chamber) in directions transverse to the axis of the tube E. In the secondary expansion chamber A the gases again expand into the interstices formed within the refractory filling, and then fiow through a similarly perforated and baflied tube F into a third expansion chamber formed by the second spherical chamber B at the outer end of the silencer casing A and similar to the primary expansion chamber C already described;

An outlet tube G, which finally leads the expanded gases to the atmosphere, extends a short distance into the third expansion chamber B, the construction of this tube G, including the conical insert G being similar to those of the inlettube D and insert D so that the outgoing gases flow first from the third expansion chamber B through the perforations in the outlet tube G transversely to the longitudinal axis thereof, along this tube G and then again change direction by flowing outwards through the perforations in the conical part of the insert G1 to the atmosphere. The several parts of the silencer are welded together, the welded joints being indicated at K.

Though the arrangement shown inFigures l and 2 comprises three expansion chambers symmetrically arranged, any desired number of expansion chambers may be used and arranged either symmetrically or asymmetrically. Further, if desired two expansion chambers only may b provided, for example as shown in Figure 3 in which the primary expansion chamber C, inlet tube D and intermediate tube E are as described with reference to Figure 2, but the exhaust gases, after expanding in the secondary expansion chamber A flow out to the atmosphere through an outlet tube H which, together with the plug H is similar to the tube G and insert G above described.

What I claim as my invention and desireto secure by Letters Patent is:

1. An exhaust silencer for internal combustion engines, comprising a primary expansion chamber packed with separate metallic balls and into which the exhaust gases flow from the engine,

a secondar expansion chamber packed with interstitial refractory material and into which the exhaust gases flow from. theprimary expansion chamber, and an outlet throughwhich the exhaust gases, flow from the secondary expansion chamber after expanding into the interstices of the refractory packing therein;

An exhaust silencer as claimed in claim 1, having baiiled conduits through which the exhaust'gasesenter and leave eachexpansion chamher the. saidbaiiledv conduits causing the gases to enter and leave: each chamber in directions transvezse to the longitudinal axis of said conduits.

3. An exhaust silencer as claimed in claim 1. in which the-inlet end of the silencer is furnished with" a conical plug flaring towards the adjacent primary expansion chamber and having-its conical wall perforated, the enteringexhaust gases flowing'throughtli perforations in directions transverse to the longitudinal axis of the plug;

4. An exhaust silencer as claimed in claim 1, in which the outlet endof the silencer is provided with a. conical plug flaring towards the adjacent expansion chamber and having'its conical wall perforated, the exhaust gases flowingout through the perforations in directions transverse to the longitudinal axis of the plug.

5. An exhaust silencer for internal combustion engines, comprising a primary expansion chamber packed with metallic balls, an exhaust gas inlet conduit through which the exhaust gases flow from the engine into the primary expansion chamber, abafiie at the inner end of the said inlet conduit within the primary expansion chamber,

therbaille deflecting the incoming exhaust gases into thcprimary expansion chamber in directions transverse to the longitudinal axis of the inlet conduit, 21 secondary expansion chamber packed with interstitial refractory material, an intermediate conduitextendingfrom the primary expansion chamber into the secondary expansion chamber; two bafiles on the intermediate conduit within thetwo'chambers respectively, said bafiles constraining the exhaust gases to enter and leave the intermediate conduit in directions transverse to. the longitudinal axisthereof, an outlet conduit leading from the secondary expansion chamber, a baiiie at the inner end of the outlet conduit, said baflie constrainin the exhaust gases leaving the secondary expansion chamber to enter the outlet conduit in directions transverse to the longitudinal axis'thereof, and a hollow plug having a conical perforated wall arrangedin the exhaust gas inlet conduit with the conical wall of said plug I'll flaring towards the adjacent primary expansion chamber, the exhaust gases from the engine flowing through the perforations in the plug in directions transverse to the longitudinal axis of the exhaust gas inlet conduit.

6. An exhaust silencer for internal combustion engines, comprising a primary expansion chamber packed with metallic balls, anexhaust gas inlet conduit through which the exhaust gases flow from the engine into the primary expansion chamber, a baiiie at the inner end of said inlet conduit Within the primary expansion chamber, the-bathe deflecting the incoming exhaust gases into the primary expansion chamber in directions transverse to the longitudinal axis of the inlet conduit, a secondary expansion chamber packed with interstitial refractory material, an intermediate conduit extending from the primary ex pansion chamber into the secondary expansion chamber, two bafiles on the intermediate conduit Within the twochambersrespectively, saidibaflles constraining the. exhaust gases to enter and leave the intermediate conduit indirections transverse to the longitudinal axis'thereof; a third expansion chamber packed with separate metallic balls, 8. second intermediate conduit extending from the secondary expansion chamber into the third expansion chamber; two battles on the second intermediate conduit within the secondary and third expansion chambers respectively, said baflles constraining the-exhaust gases to enter andleave the second intermediate conduit in directions transverse to the longitudinal axis thereof, an outlet conduit leading from the third expansion chamher, a baffle atthe inner end of the outlet conduit. said baille constraining the exhaust gases-leaving the third expansion chamber to enter the outlet conduit in directions transverse to the longitudinal axis thereof, a hollow plug having a conical I perforatedwall arranged in the exhaust gas inlet conduit With the conical wall of saidplug flexing towards the adjacent primary expansion chamber, the exhaust gases from the engine flowing through the perforations in the said plug in directions'transverse to the longitudinal axis of the exhaust gas inlet conduit, and a second hollow plug havinga conical perforated wall arranged in the exhaust gas outlet conduit with the conical wall of said second plug flaring towards-the adjacent third expansion chamber, the exhaust gases from the engine flowing through the perforations in the second plug in directions transverse to the longitudinal axis of'the exhaust gas outlet conduit.

7. An exhaust silencer as claimed in claim 5, in which a hollow plug having a conical periorated wall is'arranged in the outlet conduit with the conical wall flaring towards the adjacent secondar expansion chamber, the exhaust gases flowing out through the perforations in the plug in directions transverse to the longitudinal axis of the outlet conduit.

8. A silencerasclaimed in claim 5, in which the inlet, outlet and intermediate conduits are in the form of tubes having a plurality of transverse apertures or perforations adjacent to the associated baffles.

9. A silencer asclaimed in claim 6, in which the inlet, outlet and intermediate conduits are in the form of tubes having a plurality of transverse apertures or perforations. adjacent to the associated bafiles.

DEWAN CHAND 

